[RFC PATCH v1 07/18] x86: Extend the early_memmap support with additional attrs

Tom Lendacky
2016-04-26T22:57:07Z

Add to the early_memmap support to be able to specify encrypted and
un-encrypted mappings with and without write-protection. The use of
write-protection is necessary when encrypting data "in place". The
write-protect attribute is considered cacheable for loads, but not
stores. This implies that the hardware will never give the core a
dirty line with this memtype.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/include/asm/fixmap.h | 9 +++++++++
arch/x86/include/asm/pgtable_types.h | 8 ++++++++
arch/x86/mm/ioremap.c | 28 ++++++++++++++++++++++++++++
include/asm-generic/early_ioremap.h | 2 ++
mm/early_ioremap.c | 15 +++++++++++++++
5 files changed, 62 insertions(+)

diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 83e91f0..4d41878 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -160,6 +160,15 @@ static inline void __set_fixmap(enum fixed_addresses idx,
*/
#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_IO_NOCACHE

+void __init *early_memremap_enc(resource_size_t phys_addr,
+ unsigned long size);
+void __init *early_memremap_enc_wp(resource_size_t phys_addr,
+ unsigned long size);
+void __init *early_memremap_dec(resource_size_t phys_addr,
+ unsigned long size);
+void __init *early_memremap_dec_wp(resource_size_t phys_addr,
+ unsigned long size);
+
#include <asm-generic/fixmap.h>

#define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index fda7877..6291248 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -154,6 +154,7 @@ enum page_cache_mode {

#define _PAGE_CACHE_MASK (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)
#define _PAGE_NOCACHE (cachemode2protval(_PAGE_CACHE_MODE_UC))
+#define _PAGE_CACHE_WP (cachemode2protval(_PAGE_CACHE_MODE_WP))

#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
@@ -182,6 +183,7 @@ enum page_cache_mode {
#define __PAGE_KERNEL_VVAR (__PAGE_KERNEL_RO | _PAGE_USER)
#define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE)
#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE)
+#define __PAGE_KERNEL_WP (__PAGE_KERNEL | _PAGE_CACHE_WP)

#define __PAGE_KERNEL_IO (__PAGE_KERNEL)
#define __PAGE_KERNEL_IO_NOCACHE (__PAGE_KERNEL_NOCACHE)
@@ -196,6 +198,12 @@ enum page_cache_mode {
#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | \
_PAGE_DIRTY | _PAGE_ENC)

+#define __PAGE_KERNEL_ENC (__PAGE_KERNEL | _PAGE_ENC)
+#define __PAGE_KERNEL_ENC_WP (__PAGE_KERNEL_WP | _PAGE_ENC)
+
+#define __PAGE_KERNEL_DEC (__PAGE_KERNEL)
+#define __PAGE_KERNEL_DEC_WP (__PAGE_KERNEL_WP)
+
#define PAGE_KERNEL __pgprot(__PAGE_KERNEL | _PAGE_ENC)
#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO | _PAGE_ENC)
#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC | _PAGE_ENC)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 77dadf5..14c7ed5 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -420,6 +420,34 @@ void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
}

+/* Remap memory with encryption */
+void __init *early_memremap_enc(resource_size_t phys_addr,
+ unsigned long size)
+{
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_ENC);
+}
+
+/* Remap memory with encryption and write-protected */
+void __init *early_memremap_enc_wp(resource_size_t phys_addr,
+ unsigned long size)
+{
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_ENC_WP);
+}
+
+/* Remap memory without encryption */
+void __init *early_memremap_dec(resource_size_t phys_addr,
+ unsigned long size)
+{
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_DEC);
+}
+
+/* Remap memory without encryption and write-protected */
+void __init *early_memremap_dec_wp(resource_size_t phys_addr,
+ unsigned long size)
+{
+ return early_memremap_prot(phys_addr, size, __PAGE_KERNEL_DEC_WP);
+}
+
static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;

static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
diff --git a/include/asm-generic/early_ioremap.h b/include/asm-generic/early_ioremap.h
index 734ad4d..2edef8d 100644
--- a/include/asm-generic/early_ioremap.h
+++ b/include/asm-generic/early_ioremap.h
@@ -13,6 +13,8 @@ extern void *early_memremap(resource_size_t phys_addr,
unsigned long size);
extern void *early_memremap_ro(resource_size_t phys_addr,
unsigned long size);
+extern void *early_memremap_prot(resource_size_t phys_addr,
+ unsigned long size, unsigned long prot_val);
extern void early_iounmap(void __iomem *addr, unsigned long size);
extern void early_memunmap(void *addr, unsigned long size);

diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c
index 6d5717b..d71b98b 100644
--- a/mm/early_ioremap.c
+++ b/mm/early_ioremap.c
@@ -226,6 +226,14 @@ early_memremap_ro(resource_size_t phys_addr, unsigned long size)
}
#endif

+void __init *
+early_memremap_prot(resource_size_t phys_addr, unsigned long size,
+ unsigned long prot_val)
+{
+ return (__force void *)__early_ioremap(phys_addr, size,
+ __pgprot(prot_val));
+}
+
#define MAX_MAP_CHUNK (NR_FIX_BTMAPS << PAGE_SHIFT)

void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
@@ -267,6 +275,13 @@ early_memremap_ro(resource_size_t phys_addr, unsigned long size)
return (void *)phys_addr;
}

+void __init *
+early_memremap_prot(resource_size_t phys_addr, unsigned long size,
+ unsigned long prot_val)
+{
+ return (void *)phys_addr;
+}
+
void __init early_iounmap(void __iomem *addr, unsigned long size)